/Engine/Source/Runtime/Engine/Classes/Engine/Canvas.h
Measures a string, optionally stopped after the specified horizontal offset in pixels is reached.
static void MeasureStringInternal ( [FTextSizingParameters](API\Runtime\Engine\FTextSizingParameters) & Parameters, const TCHAR *const pText, const int32 TextLength, const int32 StopAfterHorizontalOffset, const [ELastCharacterIndexFormat](API\Runtime\Engine\Engine\UCanvas\ELastCharacterIndexFormat) CharIndexFormat, int32 & OutLastCharacterIndex )